Protocol

Procedures for measuring γ-secretase activity in membranes prepared from HEK293 cells expressing APP have been described previously (Zhang L et al Biochemistry 40, 5049-5055). Intact HEK293 cells expressing either APP or NΔE are treated with various concentrations of LY- 411,575 for 4 hours at 37 °C. In the case of cells expressing NΔE, cells are lysed, the cell lysates are separated on a 4-12% NuPAGE gel, and the processed NICD fragment is detected via Western blot with a cleavage site-specific antibody. The inhibition of NICD production is quantified by spot densitometric analysis using FluorChem. In the case of cells expressing APP, the conditioned medium is collected, centrifuged at 10,000 × g for 5 minutes to remove cell debris, and stored at -20 °C prior to the determination of Aβ levels. Aβ40 and -42 produced in HEK293 membrane- and cell-based assays, as well as plasma Aβ40 and cortex Aβ40 from TgCRND8 mice, are analyzed without pretreatment using an electrochemiluminescence detection-based immunoassay. Plasma Aβ42 is measured by enzyme-linked immunosorbent assay. A commercially available enzyme-linked immunosorbent assay kit is used to measure cortex Aβ42 according to the manufacturer''s instructions.

DNA/PI staining is performed using standard methodologies. Briefly, 1 × 106 cells are permeabilized with 100% ethanol in the presence of 15% FBS. The cells are washed and then treated for 15 minutes at 37 °C with 10 mg/mL RNAse. PI (5 mg/mL) is added, and the cells incubated for 1 hour at 4 °C prior to analysis by flow cytometry with 10 000 cells analysed per gated determination. The results are confirmed using the Immunotech Annexin V staining kit following the manufacturers’ instructions. At least three independent experiments are performed showing similar results.(Only for Reference)

Solubility (25°C)

Add solvents to the product individually and in order(Data is from Selleck tests instead of citations):
30% PEG400+0.5% Tween80+5% propylene glycolFor best results, use promptly after mixing.

30 mg/mL

* Please note that Selleck tests the solubility of all compounds in-house, and the actual solubility may differ slightly from published values. This is normal and is due to slight batch-to-batch variations.

Molecular mass (molecular weight) is the mass of one molecule of a substance and is expressed in the unified atomic mass units (u). (1 u is equal to 1/12 the mass of one atom of carbon-12)
Molar mass (molar weight) is the mass of one mole of a substance and is expressed in g/mol.

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Tech Support

Answers to questions you may have can be found in the inhibitor handling instructions. Topics include how to prepare stock solutions, how to store inhibitors, and issues that need special attention for cell-based assays and animal experiments.